Message-ID: <20251011193847.1836454-8-michal.winiarski@intel.com>
Date: Sat, 11 Oct 2025 21:38:28 +0200
From: Michał Winiarski <michal.winiarski@...el.com>
To: Alex Williamson <alex.williamson@...hat.com>, Lucas De Marchi
	<lucas.demarchi@...el.com>, Thomas Hellström
	<thomas.hellstrom@...ux.intel.com>, Rodrigo Vivi <rodrigo.vivi@...el.com>,
	Jason Gunthorpe <jgg@...pe.ca>, Yishai Hadas <yishaih@...dia.com>, Kevin Tian
	<kevin.tian@...el.com>, Shameer Kolothum
	<shameerali.kolothum.thodi@...wei.com>, <intel-xe@...ts.freedesktop.org>,
	<linux-kernel@...r.kernel.org>, <kvm@...r.kernel.org>
CC: <dri-devel@...ts.freedesktop.org>, Matthew Brost
	<matthew.brost@...el.com>, Michal Wajdeczko <michal.wajdeczko@...el.com>,
	Jani Nikula <jani.nikula@...ux.intel.com>, Joonas Lahtinen
	<joonas.lahtinen@...ux.intel.com>, Tvrtko Ursulin <tursulin@...ulin.net>,
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, "Lukasz
 Laguna" <lukasz.laguna@...el.com>, Michał Winiarski
	<michal.winiarski@...el.com>
Subject: [PATCH 07/26] drm/xe/pf: Add support for encap/decap of bitstream to/from packet

Add debugfs handlers for migration state and handle bitstream
.read()/.write() to convert from bitstream to/from migration data
packets.
As descriptor/trailer are handled at this layer - add handling for both
save and restore side.

Signed-off-by: Michał Winiarski <michal.winiarski@...el.com>
---
 drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c   |  18 +
 drivers/gpu/drm/xe/xe_gt_sriov_pf_control.h   |   1 +
 drivers/gpu/drm/xe/xe_sriov_pf.c              |   1 +
 drivers/gpu/drm/xe/xe_sriov_pf_control.c      |   5 +
 drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c      |  45 +++
 drivers/gpu/drm/xe/xe_sriov_pf_migration.c    |  56 +++
 .../gpu/drm/xe/xe_sriov_pf_migration_data.c   | 353 ++++++++++++++++++
 .../gpu/drm/xe/xe_sriov_pf_migration_data.h   |   5 +
 .../gpu/drm/xe/xe_sriov_pf_migration_types.h  |   9 +
 9 files changed, 493 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c
index 04a4e92133c2e..092d3d710bca1 100644
--- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c
+++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c
@@ -814,6 +814,23 @@ bool xe_gt_sriov_pf_control_check_vf_data_wip(struct xe_gt *gt, unsigned int vfi
 	return pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_MIGRATION_DATA_WIP);
 }
 
+/**
+ * xe_gt_sriov_pf_control_vf_data_eof() - indicate the end of SR-IOV VF migration data production
+ * @gt: the &struct xe_gt
+ * @vfid: the VF identifier
+ *
+ * This function is for PF only.
+ */
+void xe_gt_sriov_pf_control_vf_data_eof(struct xe_gt *gt, unsigned int vfid)
+{
+	struct wait_queue_head *wq = xe_sriov_pf_migration_waitqueue(gt_to_xe(gt), vfid);
+
+	if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_MIGRATION_DATA_WIP))
+		pf_enter_vf_state_machine_bug(gt, vfid);
+
+	wake_up_all(wq);
+}
+
 static void pf_exit_vf_save_wip(struct xe_gt *gt, unsigned int vfid)
 {
 	pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_WIP);
@@ -840,6 +857,7 @@ static bool pf_handle_vf_save_wip(struct xe_gt *gt, unsigned int vfid)
 	if (!pf_check_vf_state(gt, vfid, XE_GT_SRIOV_STATE_SAVE_WIP))
 		return false;
 
+	xe_gt_sriov_pf_control_vf_data_eof(gt, vfid);
 	pf_exit_vf_save_wip(gt, vfid);
 	pf_enter_vf_saved(gt, vfid);
 
diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.h b/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.h
index 2e121e8132dcf..caf20dd063b1b 100644
--- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.h
+++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.h
@@ -15,6 +15,7 @@ int xe_gt_sriov_pf_control_init(struct xe_gt *gt);
 void xe_gt_sriov_pf_control_restart(struct xe_gt *gt);
 
 bool xe_gt_sriov_pf_control_check_vf_data_wip(struct xe_gt *gt, unsigned int vfid);
+void xe_gt_sriov_pf_control_vf_data_eof(struct xe_gt *gt, unsigned int vfid);
 
 int xe_gt_sriov_pf_control_pause_vf(struct xe_gt *gt, unsigned int vfid);
 int xe_gt_sriov_pf_control_resume_vf(struct xe_gt *gt, unsigned int vfid);
diff --git a/drivers/gpu/drm/xe/xe_sriov_pf.c b/drivers/gpu/drm/xe/xe_sriov_pf.c
index 95743c7af8050..5d115627f3f2f 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf.c
+++ b/drivers/gpu/drm/xe/xe_sriov_pf.c
@@ -16,6 +16,7 @@
 #include "xe_sriov_pf.h"
 #include "xe_sriov_pf_helpers.h"
 #include "xe_sriov_pf_migration.h"
+#include "xe_sriov_pf_migration_data.h"
 #include "xe_sriov_pf_service.h"
 #include "xe_sriov_printk.h"
 
diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_control.c b/drivers/gpu/drm/xe/xe_sriov_pf_control.c
index e64c7b56172c6..10e1f18aa8b11 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf_control.c
+++ b/drivers/gpu/drm/xe/xe_sriov_pf_control.c
@@ -6,6 +6,7 @@
 #include "xe_device.h"
 #include "xe_gt_sriov_pf_control.h"
 #include "xe_sriov_pf_control.h"
+#include "xe_sriov_pf_migration_data.h"
 #include "xe_sriov_printk.h"
 
 /**
@@ -165,6 +166,10 @@ int xe_sriov_pf_control_save_vf(struct xe_device *xe, unsigned int vfid)
 	unsigned int id;
 	int ret;
 
+	ret = xe_sriov_pf_migration_data_save_init(xe, vfid);
+	if (ret)
+		return ret;
+
 	for_each_gt(gt, xe, id) {
 		ret = xe_gt_sriov_pf_control_save_vf(gt, vfid);
 		if (ret)
diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c b/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c
index 74eeabef91c57..ce780719760a6 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c
+++ b/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c
@@ -13,6 +13,7 @@
 #include "xe_sriov_pf_control.h"
 #include "xe_sriov_pf_debugfs.h"
 #include "xe_sriov_pf_helpers.h"
+#include "xe_sriov_pf_migration_data.h"
 #include "xe_sriov_pf_service.h"
 #include "xe_sriov_printk.h"
 #include "xe_tile_sriov_pf_debugfs.h"
@@ -71,6 +72,7 @@ static void pf_populate_pf(struct xe_device *xe, struct dentry *pfdent)
  *      /sys/kernel/debug/dri/BDF/
  *      ├── sriov
  *      │   ├── vf1
+ *      │   │   ├── migration_data
  *      │   │   ├── pause
  *      │   │   ├── reset
  *      │   │   ├── resume
@@ -159,6 +161,48 @@ DEFINE_VF_CONTROL_ATTRIBUTE(reset_vf);
 DEFINE_VF_RW_CONTROL_ATTRIBUTE(save_vf);
 DEFINE_VF_RW_CONTROL_ATTRIBUTE(restore_vf);
 
+static ssize_t data_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
+{
+	struct dentry *dent = file_dentry(file);
+	struct dentry *vfdentry = dent->d_parent;
+	struct dentry *migration_dentry = vfdentry->d_parent;
+	unsigned int vfid = (uintptr_t)vfdentry->d_inode->i_private;
+	struct xe_device *xe = migration_dentry->d_inode->i_private;
+
+	xe_assert(xe, vfid);
+	xe_sriov_pf_assert_vfid(xe, vfid);
+
+	if (*pos)
+		return -ESPIPE;
+
+	return xe_sriov_pf_migration_data_write(xe, vfid, buf, count);
+}
+
+static ssize_t data_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+	struct dentry *dent = file_dentry(file);
+	struct dentry *vfdentry = dent->d_parent;
+	struct dentry *migration_dentry = vfdentry->d_parent;
+	unsigned int vfid = (uintptr_t)vfdentry->d_inode->i_private;
+	struct xe_device *xe = migration_dentry->d_inode->i_private;
+
+	xe_assert(xe, vfid);
+	xe_sriov_pf_assert_vfid(xe, vfid);
+
+	if (*ppos)
+		return -ESPIPE;
+
+	return xe_sriov_pf_migration_data_read(xe, vfid, buf, count);
+}
+
+static const struct file_operations data_vf_fops = {
+	.owner		= THIS_MODULE,
+	.open		= simple_open,
+	.write		= data_write,
+	.read		= data_read,
+	.llseek		= default_llseek,
+};
+
 static void pf_populate_vf(struct xe_device *xe, struct dentry *vfdent)
 {
 	debugfs_create_file("pause", 0200, vfdent, xe, &pause_vf_fops);
@@ -167,6 +211,7 @@ static void pf_populate_vf(struct xe_device *xe, struct dentry *vfdent)
 	debugfs_create_file("reset", 0200, vfdent, xe, &reset_vf_fops);
 	debugfs_create_file("save", 0600, vfdent, xe, &save_vf_fops);
 	debugfs_create_file("restore", 0600, vfdent, xe, &restore_vf_fops);
+	debugfs_create_file("migration_data", 0600, vfdent, xe, &data_vf_fops);
 }
 
 static void pf_populate_with_tiles(struct xe_device *xe, struct dentry *dent, unsigned int vfid)
diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_migration.c b/drivers/gpu/drm/xe/xe_sriov_pf_migration.c
index d39cee66589b5..9cc178126cbdc 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf_migration.c
+++ b/drivers/gpu/drm/xe/xe_sriov_pf_migration.c
@@ -56,6 +56,18 @@ static bool pf_check_migration_support(struct xe_device *xe)
 	return IS_ENABLED(CONFIG_DRM_XE_DEBUG);
 }
 
+static void pf_migration_cleanup(struct drm_device *dev, void *arg)
+{
+	struct xe_sriov_pf_migration *migration = arg;
+
+	if (!IS_ERR_OR_NULL(migration->pending))
+		xe_sriov_pf_migration_data_free(migration->pending);
+	if (!IS_ERR_OR_NULL(migration->trailer))
+		xe_sriov_pf_migration_data_free(migration->trailer);
+	if (!IS_ERR_OR_NULL(migration->descriptor))
+		xe_sriov_pf_migration_data_free(migration->descriptor);
+}
+
 /**
  * xe_sriov_pf_migration_init() - Initialize support for SR-IOV VF migration.
  * @xe: the &struct xe_device
@@ -65,6 +77,7 @@ static bool pf_check_migration_support(struct xe_device *xe)
 int xe_sriov_pf_migration_init(struct xe_device *xe)
 {
 	unsigned int n, totalvfs;
+	int err;
 
 	xe_assert(xe, IS_SRIOV_PF(xe));
 
@@ -76,7 +89,15 @@ int xe_sriov_pf_migration_init(struct xe_device *xe)
 	for (n = 1; n <= totalvfs; n++) {
 		struct xe_sriov_pf_migration *migration = pf_pick_migration(xe, n);
 
+		err = drmm_mutex_init(&xe->drm, &migration->lock);
+		if (err)
+			return err;
+
 		init_waitqueue_head(&migration->wq);
+
+		err = drmm_add_action_or_reset(&xe->drm, pf_migration_cleanup, migration);
+		if (err)
+			return err;
 	}
 
 	return 0;
@@ -162,6 +183,36 @@ xe_sriov_pf_migration_consume(struct xe_device *xe, unsigned int vfid)
 	return data;
 }
 
+static int pf_handle_descriptor(struct xe_device *xe, unsigned int vfid,
+				struct xe_sriov_pf_migration_data *data)
+{
+	if (data->tile != 0 || data->gt != 0)
+		return -EINVAL;
+
+	xe_sriov_pf_migration_data_free(data);
+
+	return 0;
+}
+
+static int pf_handle_trailer(struct xe_device *xe, unsigned int vfid,
+			     struct xe_sriov_pf_migration_data *data)
+{
+	struct xe_gt *gt;
+	u8 gt_id;
+
+	if (data->tile != 0 || data->gt != 0)
+		return -EINVAL;
+	if (data->offset != 0 || data->size != 0 || data->buff || data->bo)
+		return -EINVAL;
+
+	xe_sriov_pf_migration_data_free(data);
+
+	for_each_gt(gt, xe, gt_id)
+		xe_gt_sriov_pf_control_vf_data_eof(gt, vfid);
+
+	return 0;
+}
+
 /**
  * xe_sriov_pf_migration_produce() - Produce a SR-IOV VF migration data packet for device to process
  * @xe: the &struct xe_device
@@ -180,6 +231,11 @@ int xe_sriov_pf_migration_produce(struct xe_device *xe, unsigned int vfid,
 	if (!IS_SRIOV_PF(xe))
 		return -ENODEV;
 
+	if (data->type == XE_SRIOV_MIG_DATA_DESCRIPTOR)
+		return pf_handle_descriptor(xe, vfid, data);
+	else if (data->type == XE_SRIOV_MIG_DATA_TRAILER)
+		return pf_handle_trailer(xe, vfid, data);
+
 	gt = xe_device_get_gt(xe, data->gt);
 	if (!gt || data->tile != gt->tile->id) {
 		xe_sriov_err_ratelimited(xe, "VF%d Unknown GT - tile_id:%d, gt_id:%d\n",
diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_migration_data.c b/drivers/gpu/drm/xe/xe_sriov_pf_migration_data.c
index cfc6b512c6674..9a2777dcf9a6b 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf_migration_data.c
+++ b/drivers/gpu/drm/xe/xe_sriov_pf_migration_data.c
@@ -5,7 +5,45 @@
 
 #include "xe_bo.h"
 #include "xe_device.h"
+#include "xe_sriov_pf_helpers.h"
+#include "xe_sriov_pf_migration.h"
 #include "xe_sriov_pf_migration_data.h"
+#include "xe_sriov_printk.h"
+
+static struct mutex *pf_migration_mutex(struct xe_device *xe, unsigned int vfid)
+{
+	xe_assert(xe, IS_SRIOV_PF(xe));
+	xe_assert(xe, vfid <= xe_sriov_pf_get_totalvfs(xe));
+	return &xe->sriov.pf.vfs[vfid].migration.lock;
+}
+
+static struct xe_sriov_pf_migration_data **pf_pick_pending(struct xe_device *xe, unsigned int vfid)
+{
+	xe_assert(xe, IS_SRIOV_PF(xe));
+	xe_assert(xe, vfid <= xe_sriov_pf_get_totalvfs(xe));
+	lockdep_assert_held(pf_migration_mutex(xe, vfid));
+
+	return &xe->sriov.pf.vfs[vfid].migration.pending;
+}
+
+static struct xe_sriov_pf_migration_data **
+pf_pick_descriptor(struct xe_device *xe, unsigned int vfid)
+{
+	xe_assert(xe, IS_SRIOV_PF(xe));
+	xe_assert(xe, vfid <= xe_sriov_pf_get_totalvfs(xe));
+	lockdep_assert_held(pf_migration_mutex(xe, vfid));
+
+	return &xe->sriov.pf.vfs[vfid].migration.descriptor;
+}
+
+static struct xe_sriov_pf_migration_data **pf_pick_trailer(struct xe_device *xe, unsigned int vfid)
+{
+	xe_assert(xe, IS_SRIOV_PF(xe));
+	xe_assert(xe, vfid <= xe_sriov_pf_get_totalvfs(xe));
+	lockdep_assert_held(pf_migration_mutex(xe, vfid));
+
+	return &xe->sriov.pf.vfs[vfid].migration.trailer;
+}
 
 static bool data_needs_bo(struct xe_sriov_pf_migration_data *data)
 {
@@ -133,3 +171,318 @@ int xe_sriov_pf_migration_data_init_from_hdr(struct xe_sriov_pf_migration_data *
 
 	return mig_data_init(data);
 }
+
+static ssize_t vf_mig_data_hdr_read(struct xe_sriov_pf_migration_data *data,
+				    char __user *buf, size_t len)
+{
+	loff_t offset = sizeof(data->hdr) - data->hdr_remaining;
+
+	if (!data->hdr_remaining)
+		return -EINVAL;
+
+	if (len > data->hdr_remaining)
+		len = data->hdr_remaining;
+
+	if (copy_to_user(buf, (void *)&data->hdr + offset, len))
+		return -EFAULT;
+
+	data->hdr_remaining -= len;
+
+	return len;
+}
+
+static ssize_t vf_mig_data_read(struct xe_sriov_pf_migration_data *data,
+				char __user *buf, size_t len)
+{
+	if (len > data->remaining)
+		len = data->remaining;
+
+	if (copy_to_user(buf, data->vaddr + (data->size - data->remaining), len))
+		return -EFAULT;
+
+	data->remaining -= len;
+
+	return len;
+}
+
+static ssize_t __vf_mig_data_read_single(struct xe_sriov_pf_migration_data **data,
+					 unsigned int vfid, char __user *buf, size_t len)
+{
+	ssize_t copied = 0;
+
+	if ((*data)->hdr_remaining)
+		copied = vf_mig_data_hdr_read(*data, buf, len);
+	else
+		copied = vf_mig_data_read(*data, buf, len);
+
+	if ((*data)->remaining == 0 && (*data)->hdr_remaining == 0) {
+		xe_sriov_pf_migration_data_free(*data);
+		*data = NULL;
+	}
+
+	return copied;
+}
+
+static struct xe_sriov_pf_migration_data **vf_mig_pick_data(struct xe_device *xe, unsigned int vfid)
+{
+	struct xe_sriov_pf_migration_data **data;
+
+	data = pf_pick_descriptor(xe, vfid);
+	if (*data)
+		return data;
+
+	data = pf_pick_pending(xe, vfid);
+	if (*data == NULL)
+		*data = xe_sriov_pf_migration_consume(xe, vfid);
+	if (!IS_ERR_OR_NULL(*data))
+		return data;
+	else if (IS_ERR(*data) && PTR_ERR(*data) != -ENODATA)
+		return data;
+
+	data = pf_pick_trailer(xe, vfid);
+	if (*data)
+		return data;
+
+	return ERR_PTR(-ENODATA);
+}
+
+static ssize_t vf_mig_data_read_single(struct xe_device *xe, unsigned int vfid,
+				       char __user *buf, size_t len)
+{
+	struct xe_sriov_pf_migration_data **data = vf_mig_pick_data(xe, vfid);
+
+	if (IS_ERR_OR_NULL(data))
+		return PTR_ERR(data);
+
+	return __vf_mig_data_read_single(data, vfid, buf, len);
+}
+
+/**
+ * xe_sriov_pf_migration_data_read() - Read migration data from the device
+ * @gt: the &struct xe_device
+ * @vfid: the VF identifier
+ * @buf: start address of userspace buffer
+ * @len: requested read size from userspace
+ *
+ * Return: number of bytes that has been successfully read
+ *	   0 if no more migration data is available
+ *	   -errno on failure
+ */
+ssize_t xe_sriov_pf_migration_data_read(struct xe_device *xe, unsigned int vfid,
+					char __user *buf, size_t len)
+{
+	ssize_t ret, consumed = 0;
+
+	xe_assert(xe, IS_SRIOV_PF(xe));
+
+	ret = mutex_lock_interruptible(pf_migration_mutex(xe, vfid));
+	if (ret)
+		return ret;
+
+	while (consumed < len) {
+		ret = vf_mig_data_read_single(xe, vfid, buf, len - consumed);
+		if (ret == -ENODATA)
+			goto out;
+		if (ret < 0) {
+			mutex_unlock(pf_migration_mutex(xe, vfid));
+			return ret;
+		}
+
+		consumed += ret;
+		buf += ret;
+	}
+
+out:
+	mutex_unlock(pf_migration_mutex(xe, vfid));
+	return consumed;
+}
+
+static ssize_t vf_mig_hdr_write(struct xe_sriov_pf_migration_data *data,
+				const char __user *buf, size_t len)
+{
+	loff_t offset = sizeof(data->hdr) - data->hdr_remaining;
+	int ret;
+
+	if (WARN_ON(!data->hdr_remaining))
+		return -EINVAL;
+
+	if (len > data->hdr_remaining)
+		len = data->hdr_remaining;
+
+	if (copy_from_user((void *)&data->hdr + offset, buf, len))
+		return -EFAULT;
+
+	data->hdr_remaining -= len;
+
+	if (!data->hdr_remaining) {
+		ret = xe_sriov_pf_migration_data_init_from_hdr(data);
+		if (ret)
+			return ret;
+	}
+
+	return len;
+}
+
+static ssize_t vf_mig_data_write(struct xe_sriov_pf_migration_data *data,
+				 const char __user *buf, size_t len)
+{
+	if (len > data->remaining)
+		len = data->remaining;
+
+	if (copy_from_user(data->vaddr + (data->size - data->remaining), buf, len))
+		return -EFAULT;
+
+	data->remaining -= len;
+
+	return len;
+}
+
+static ssize_t vf_mig_data_write_single(struct xe_device *xe, unsigned int vfid,
+					const char __user *buf, size_t len)
+{
+	struct xe_sriov_pf_migration_data **data = pf_pick_pending(xe, vfid);
+	int ret;
+	ssize_t copied;
+
+	if (IS_ERR_OR_NULL(*data)) {
+		*data = xe_sriov_pf_migration_data_alloc(xe);
+		if (*data == NULL)
+			return -ENOMEM;
+	}
+
+	if ((*data)->hdr_remaining)
+		copied = vf_mig_hdr_write(*data, buf, len);
+	else
+		copied = vf_mig_data_write(*data, buf, len);
+
+	if ((*data)->hdr_remaining == 0 && (*data)->remaining == 0) {
+		ret = xe_sriov_pf_migration_produce(xe, vfid, *data);
+		if (ret) {
+			xe_sriov_pf_migration_data_free(*data);
+			return ret;
+		}
+
+		*data = NULL;
+	}
+
+	return copied;
+}
+
+/**
+ * xe_sriov_pf_migration_data_write() - Write migration data to the device
+ * @gt: the &struct xe_device
+ * @vfid: the VF identifier
+ * @buf: start address of userspace buffer
+ * @len: requested write size from userspace
+ *
+ * Return: number of bytes that has been successfully written
+ *	   -errno on failure
+ */
+ssize_t xe_sriov_pf_migration_data_write(struct xe_device *xe, unsigned int vfid,
+					 const char __user *buf, size_t len)
+{
+	ssize_t ret, produced = 0;
+
+	xe_assert(xe, IS_SRIOV_PF(xe));
+
+	ret = mutex_lock_interruptible(pf_migration_mutex(xe, vfid));
+	if (ret)
+		return ret;
+
+	while (produced < len) {
+		ret = vf_mig_data_write_single(xe, vfid, buf, len - produced);
+		if (ret < 0) {
+			mutex_unlock(pf_migration_mutex(xe, vfid));
+			return ret;
+		}
+
+		produced += ret;
+		buf += ret;
+	}
+
+	mutex_unlock(pf_migration_mutex(xe, vfid));
+	return produced;
+}
+
+#define MIGRATION_DESC_SIZE 4
+static size_t pf_desc_init(struct xe_device *xe, unsigned int vfid)
+{
+	struct xe_sriov_pf_migration_data **desc = pf_pick_descriptor(xe, vfid);
+	struct xe_sriov_pf_migration_data *data;
+	int ret;
+
+	data = xe_sriov_pf_migration_data_alloc(xe);
+	if (!data)
+		return -ENOMEM;
+
+	ret = xe_sriov_pf_migration_data_init(data, 0, 0, XE_SRIOV_MIG_DATA_DESCRIPTOR,
+					      0, MIGRATION_DESC_SIZE);
+	if (ret) {
+		xe_sriov_pf_migration_data_free(data);
+		return ret;
+	}
+
+	*desc = data;
+
+	return 0;
+}
+
+static void pf_pending_init(struct xe_device *xe, unsigned int vfid)
+{
+	struct xe_sriov_pf_migration_data **data = pf_pick_pending(xe, vfid);
+
+	*data = NULL;
+}
+
+#define MIGRATION_TRAILER_SIZE 0
+static int pf_trailer_init(struct xe_device *xe, unsigned int vfid)
+{
+	struct xe_sriov_pf_migration_data **trailer = pf_pick_trailer(xe, vfid);
+	struct xe_sriov_pf_migration_data *data;
+	int ret;
+
+	data = xe_sriov_pf_migration_data_alloc(xe);
+	if (!data)
+		return -ENOMEM;
+
+	ret = xe_sriov_pf_migration_data_init(data, 0, 0, XE_SRIOV_MIG_DATA_TRAILER,
+					      0, MIGRATION_TRAILER_SIZE);
+	if (ret) {
+		xe_sriov_pf_migration_data_free(data);
+		return ret;
+	}
+
+	*trailer = data;
+
+	return 0;
+}
+
+/**
+ * xe_sriov_pf_migration_data_save_init() - Initialize the pending save migration data.
+ * @gt: the &struct xe_device
+ * @vfid: the VF identifier
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int xe_sriov_pf_migration_data_save_init(struct xe_device *xe, unsigned int vfid)
+{
+	int ret;
+
+	ret = mutex_lock_interruptible(pf_migration_mutex(xe, vfid));
+	if (ret)
+		return ret;
+
+	ret = pf_desc_init(xe, vfid);
+	if (ret)
+		goto out;
+
+	ret = pf_trailer_init(xe, vfid);
+	if (ret)
+		goto out;
+
+	pf_pending_init(xe, vfid);
+
+out:
+	mutex_unlock(pf_migration_mutex(xe, vfid));
+	return ret;
+}
diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_migration_data.h b/drivers/gpu/drm/xe/xe_sriov_pf_migration_data.h
index 1dde4cfcdbc47..5b96c7f224002 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf_migration_data.h
+++ b/drivers/gpu/drm/xe/xe_sriov_pf_migration_data.h
@@ -28,5 +28,10 @@ void xe_sriov_pf_migration_data_free(struct xe_sriov_pf_migration_data *snapshot
 int xe_sriov_pf_migration_data_init(struct xe_sriov_pf_migration_data *data, u8 tile_id, u8 gt_id,
 				    unsigned int type, loff_t offset, size_t size);
 int xe_sriov_pf_migration_data_init_from_hdr(struct xe_sriov_pf_migration_data *snapshot);
+ssize_t xe_sriov_pf_migration_data_read(struct xe_device *xe, unsigned int vfid,
+					char __user *buf, size_t len);
+ssize_t xe_sriov_pf_migration_data_write(struct xe_device *xe, unsigned int vfid,
+					 const char __user *buf, size_t len);
+int xe_sriov_pf_migration_data_save_init(struct xe_device *xe, unsigned int vfid);
 
 #endif
diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_migration_types.h b/drivers/gpu/drm/xe/xe_sriov_pf_migration_types.h
index 80fdea32b884a..c5d75bb7f39c0 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf_migration_types.h
+++ b/drivers/gpu/drm/xe/xe_sriov_pf_migration_types.h
@@ -7,6 +7,7 @@
 #define _XE_SRIOV_PF_MIGRATION_TYPES_H_
 
 #include <linux/types.h>
+#include <linux/mutex_types.h>
 #include <linux/wait.h>
 
 struct xe_sriov_pf_migration_data {
@@ -32,6 +33,14 @@ struct xe_sriov_pf_migration_data {
 struct xe_sriov_pf_migration {
 	/** @wq: waitqueue used to avoid busy-waiting for snapshot production/consumption */
 	wait_queue_head_t wq;
+	/** @lock: Mutex protecting the migration data */
+	struct mutex lock;
+	/** @pending: currently processed data packet of VF resource */
+	struct xe_sriov_pf_migration_data *pending;
+	/** @trailer: data packet used to indicate the end of stream */
+	struct xe_sriov_pf_migration_data *trailer;
+	/** @descriptor: data packet containing the metadata describing the device */
+	struct xe_sriov_pf_migration_data *descriptor;
 };
 
 #endif
-- 
2.50.1

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